High Levels of Toxic Chemicals Found in English Channel Dolphins

The bottlenose dolphin Tursiops truncatus in the Normanno-Breton Gulf, or English Channel. (GECC)

(CN) – High levels of toxic pollutants – including ones banned decades ago – have been observed in the skin and blubber of bottlenose dolphins living in the English Channel, according to a new study.

The study, published Thursday in Scientific Reports, details the efforts of a team of European researchers to better understand the effects that pollutants have on coastal marine life, specifically the bottlenose dolphin. Researchers conducted an exhaustive examination of 82 free-ranging bottlenose dolphins populating the Normanno-Breton Gulf of the English Channel and made some startling discoveries.

The researchers, led by Krishna Das of the University of Liège in Belgium, found toxic chemical compounds have accumulated in the skin and blubber of bottlenose dolphins with alarming severity. Researchers found mercury, a compound that can be highly dangerous to organic life, in the dolphins’ blubber at levels that have never been seen before.

While many chemical pollutants contaminating oceans were banned by most developed nations roughly 40 years ago, the effects of those chemicals persist experienced today. The chemicals have been able to survive for so long by dissolving and being absorbed by animal fats and oils, with bottlenose dolphins and other marine life acting as a kind of bio-sponge for the chemical residue.

Das suggests that to help combat the issue, the Normanno-Breton Gulf should be designated as a special area of conservation to help protect local bottlenose dolphin populations.

“This coastal bottlenose dolphin population is one of the largest populations in Europe. Nobody knows how long these dolphins have been there, but for sure they carry legacy pollutants in their tissues. There has been no evaluation of their pollutant exposure before, and yet I hope this paper will attract attention on those population and that effort will be made to protect these dolphin even more,” Das said in an email.

Researchers point out that while bottlenose dolphins are commonly used to help scientists discover the levels of underwater contamination, the problem of toxic chemicals being absorbed by marine life stretches far deeper into the ocean. The study warns that undersea life of all kinds and operating in multiple underwater depths can be adversely affected by toxic pollutants.